M4 average speed cameras in Wiltshire road works net 1,200
More than 1,200 drivers were caught speeding in less than two months by average speed check cameras on part of the M4, the BBC has learned.
The 50mph cameras were set up along road works between Swindon and Chippenham on 18 March.
The fastest speed recorded was 107mph. How much revenue has been raised by the fines levied is not yet available.
There were 261 offences recorded in March and 948 in April. The top five speeds were between 107mph and 88mph.
'Safety at risk'
Avon and Somerset Police said the revenue stream information was not currently available because enforcement had only been in place for a short time.
The force released the information after the BBC made a Freedom of Information (FOI) request.
Insp Steve Cox, head of roads policing for Wiltshire Police, said: "Reduced speed limit zones on motorways are in place for a reason and to make that stretch of motorway as safe as possible while essential maintenance work is undertaken.
"By ignoring this reduced speed limit these drivers have put their own safety and the safety of other drivers on the road at risk."
Between April and September 2012, some 14,000 motorists were caught speeding by the average speed limit cameras on the M4 and M5 near the Almondsbury interchange at Bristol.
The fastest speed recorded was 137mph.